Morphologic and immunohistochemical changes in prostate cancer after preoperative hormonal therapy. A comparative study of radical prostatectomies.

Background: Estramustine phosphate (EMP) and flutamide (FL) were used as reversible preoperative hormonal drugs in the surgical treatment of patients with localized prostate cancer.

Methods: The authors descriptive and quantitatively examined the morphologic and immunohistochemical changes in 40 of 200 step-sectioned radical prostatectomies, obtained after treatment with EMP (25 patients) and with FL (15 patients). Of these, 28 pretreatment needlecore biopsies were available.

Results: Every specimen contained adenocarcinoma. Understaging was found in 50% of the cases and a higher Gleason score in 70%. Benign glands underwent atrophy and squamous metaplasia. Treated tumors showed cytoplasmic vacuolization, nuclear pyknosis, fibrosis and lymphocytic infiltrates. The EMP group had an 84% (P < 0.05) higher mean total regression score than the FL group. Estramustine phosphate induced a 56% (P < 0.05) and a 34% decrease in tumoral prostate specific antigen and prostate specific acid phosphatase intensity scores, respectively, versus 29% and 32% after FL. The mean proliferating cell nuclear antigen (PCNA) labeling index and the mean mitotic index of the EMP group were 52% (P < 0.05) and 70% (P < 0.05) lower than those measured in the FL group. Each FL-treated tumor and 92% of EMP-treated tumors expressed chromogranin A (ChrA); ChrA labeling correlated significantly with PCNA labeling. Seventy-six percent of EMP-treated specimens revealed venous thrombosis.

Conclusions: Estramustine phosphate induces important morphologic and immunohistochemical changes in prostate cancer with an apparent decrease of secretory and proliferative activity when compared with FL-treated tumors. These changes represent pitfalls in the diagnosis and grading of treated carcinomas. Nearly every treated adenocarcinoma of the prostate has neuroendocrine differentiation, showing increasing ChrA labeling with higher tumor stage. A significant correlation between tumor proliferation and neuroendocrine differentiation was noticed in this small cohort of patients. There was a high incidence of periprostatic venous thrombosis after EMP treatment.